add neg test

tests/neg/i4984.scala

@@ -0,0 +1,26 @@
+object Array2 {
+  def unapplySeq(x: Array[Int]): Data = new Data
+
+  final class Data {
+    def isEmpty: Boolean = false
+    def get: Data = this
+    def lengthCompare(len: Int): Int = 0
+    def apply(i: Int): Int = 3
+    def drop(n: Int): scala.Seq[String] = Seq("hello")
+    def toSeq: scala.Seq[Int] = Seq(6, 7)
+  }
+}
+
+object Test {
+  def test1(xs: Array[Int]): Int = xs match {
+    case Array2(x, y) => x + y  // error // error
+  }
+
+  def test2(xs: Array[Int]): Seq[Int] = xs match {
+    case Array2(x, y, xs:_*) => xs // error
+  }
+
+  def test3(xs: Array[Int]): Seq[Int] = xs match {
+    case Array2(xs:_*) => xs   // error
+  }
+}